1. Field of the Invention
The present invention relates to a female coupling element and to a quick coupling for releasably joining together two pipes conveying a fluid under pressure, and including such a female element.
2. Description of Related Art
WO-A-2006/092503 describes a quick coupling comprising a female element and a male element that are connected respectively to an upstream pipe and to a downstream pipe, and that are suitable for being axially engaged one in the other. Relative engagement of the male and female elements causes a valve member mounted inside a body of the female element to open, thereby putting the upstream and downstream pipes into communication. The female coupling element includes a latch slidably mounted in the body of the female element and resiliently biased towards a position for locking the male element in its engaged configuration inside the female element. In order to separate the elements of the coupling, the female element also has a press button for sliding the latch against its resilient bias and suitable for moving the latch to a position for transiently retaining the male element inside the female element. When the latch is in its transient retaining position, the valve member of the female element closes the body of the female element, while the fluid contained in the downstream pipe flows to the outside of the coupling through gaps constituted by the clearances needed to enable the coupling to operate. When the pressure inside the coupling drops down to a safety threshold, the latch is pushed automatically by its resilient bias towards a position for releasing the male element relative to the female element. The male element is then ready to be separated from the female element, without any whiplash.
In order to ensure that the latch passes safely from its transient retaining position to its position for releasing the male element, the decompression of the inside of the coupling needs to be progressive and under control. The coupling described in WO-A-2006/092503 has gaps, through which fluid flows from the downstream pipe to outside the coupling, that are of sections that are not well controlled. These gaps constitute operating clearances between parts of the coupling that slide relative to one another. As a result, obtaining determined sections for these clearance gaps would require the parts of the coupling to be of precise dimensions and that would considerably increase the cost of fabricating such a coupling.